Insulation for electrical conductors



April 1, 1930. H. 5. WITMER INSULATION FOR ELECTRICAL GONDUCTORS Filed Jan. 21, 1929 iNVENTORZ H. Wz'tmcr; BY

@- 60W NL ATTORNEY Patented Apr. 1, 1930 UNITED STATES PATENT OFFICE HAROLD G. WITMER, F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, IENNSYLVANIA, A CORPORATION OF IPENNSYLVANIA INSULATION FOR ELECTRICAL CONDUCTOBS Application filed January 21, 1929. Serial No. 334,083.

My invention relates to insulation for electrical conductors, and has for an object the provision of means for insulating two conductors from each other in such manner as 6 to permit the circulation of a cooling medium between the conductors and yet hold the conductors rigidly spaced from each other.

I will describe one form of insulation em v bodying my invention, and will then point 10 out the novel features thereof in claims.

The accompanying drawing is a perspective view illustrating two parallel electrical conductors insulated from each other in accordance with one form of my invention,

certain parts being broken away to more clearly show the construction.

Referring to the drawing, the reference characters A and B designate two electrical conductors which are parallel with each other, and each of which, in the form here shown, is ribbon-like in shape. Although I have referred to these parts as two conductors, they may be the contiguous conductor of two separate coils, or they may be parts of two adjacent turns in a single coil. Inter-1 posed between the conductors A and B are two insulating members C and D. As here shown, these insulating members are exactly alike, and each comprises a plurality of I spaced flat rectangular ribs 1, adjacent ones of which are connected together for a portion of their length near their one end 'by means of fiat integral webs 2 having the same thickness as the ribs. The insulating members are disposed between the conductors with the ribs of the one member in alignment with the ribs of the other member, but with the webs of the one member separated from the webs of the other member. If desired, the insulating members may be fastened together by means of some suitable adhesive material, such as shellac. With the insulating members arranged in this manner,- it will be noted that a plurality of passages are provided between the conductors so that free circulation of a cooling medium between the conductors is permitted, yet the conductors are rigidly spaced from each other.

My invention is particularly well adapted for the insulation of the parallel conductors in certain forms of coils for impedance bonds used in railway signaling on electrified roads, such for example, as the coil B shown in Figs. 5 and 6 in Letters Patent of the United States, No. 838,916, granted to Lewis H. Thullen on December 18, 1906. This coil is formed of two interlaced spirals which carry heavy currents and which must be suitably insulated from each other at all points. When used for insulating this form of coil, the insulating members C and D may be punched out of long strips of insulating material, and fed- Having thus described my invention, what I claim is:

1. In combination, two parallel conductors; and two similar insulating members each comprising a plurality of spaced ribs adjacent ones of which are connected together by means of integral webs, said members being disposed between said conductors in such manner that passages are provided between the conductors at the webs of the members.

2. In combination, two parallel conductors; and two insulating members'each comprising a plurality of spaced ribs, adjacent ones of which are connected together for a portion of their length by integral webs having the same thickness as the ribs, said members being disposed between said conductors with the ribs of one member in alignment with the ribs of the other member but with the webs of the one member spaced from the webs of the other member.

3. In combination, two parallel conductors; and two insulating members each comprising a plurality of flat spaced rectangular shaped ribs connected together for a portion of their length at some point other than their centers by means of integral webs, said members being disposed between said conductors in such manner that openings are provided 5 between the ribs and past the webs of both members to permit circulation of a cooling medium between the conductors.

4.'In combination, two parallel conductors, two insulating members each comprising a plurality of spaced ribs adjacent ones of which are connected together for a portion of their length by means of integral webs, said members being disposed between said conductors in such manner that the openings between the ribs of the one member extend past the webs of the other member.

In testimony whereof I afiix my signature.

\ HAROLD G. WITMER. 

